Liquid crystal display including O-type and E-type polarizer

ABSTRACT

The disclosure pertains to the devices of information displays, in particular liquid crystal displays, and could be utilized in indication devices for various purposes. Liquid crystal displays, according to this disclosure, contain at least one layer of liquid crystal placed between two plates, on each plates there has been formed or applied at least one electrode or a system of electrodes, or an active matrix, and at least one layer of polarizer; while at least one polarizing layer is the E-type polarizer and at least one polarizing layer is an O-type polarizer. The polarizer, according to the invention, consists of at least two polarizers, at least one of which is the E-type polarizer and at least one is the O-type polarizer.

RELATED APPLICATIONS

This is a divisional application of U.S. application Ser. No.10/240,531, which entered the United States national stage on Apr. 14,2003 under 35 U.S.C. § 371 for PCT/US01/13189 filed Apr. 24, 2001, whichclaims priority to RU200110172 filed Apr. 24, 2000, the disclosures ofall of which are incorporated herein by reference.

BACKGROUND

1. Field

The disclosure pertains to the technology of information displays, inparticular to the liquid crystal displays (LCD), and could be utilizedin devices of various configurations.

2. Description of the Related Art

The following references, which are incorporated by reference are ofinterest in this disclosure.

-   1. L. K. Vistrin. GVHO, 1983, vol. XXVII, 2nd ed., pp. 141-148-   2. U.S. Pat. No. 5,007,942, 1991-   3. RU 2120651, 1998-   4. U.S. Pat. No. 5,739,296, 1998

These references are now further discussed.

There are liquid crystal (LC) displays, which are realized having twoparallel flat plates, the inside surfaces of which are coated withpatterns of optically transparent conducting material and the alignmentlayer. After the assembly of the plates the space between them is filledwith liquid crystal, which forms a layer 5-20 μm thick and plays therole of the active medium, which changes its optical qualities (angle oftwist of the polarizing plane) under the influence of electric field.The change in the optical qualities is registered in the cross-orientedpolarizers, which are usually applied onto the inside surfaces of theplates. Therefore, the areas of the display, on the electrodes of whichelectrical field is not applied, will look bright (open state), whilethe areas, the electrodes of which are under the electrical field, willlook dark (closed state) (L. K. Vistrin. GVHO, 1983, vol. XXVII, 2nded., pp. 141-148).

The main drawback of the described above displays is the limited viewingangle. This is because the multi-layered structure of the LC display iseffectively controlled by the flux of light propagating towards thesurface of the display within a limited solid angle. The polarizers insuch displays are polymer-based, such as polyvinyl-alcohol, which ismade optically anisotropic by uniform stretching of a thin film (U.S.Pat. No. 5,007,942, 1991). The optical anisotropy is obtained as aresult of ordering of the polymer molecules along the direction ofstretching. When exposed to iodine vapor or iodine-containing solutionor an organic dye, the film is colored with the intensity of colordepending of the direction of the vector of the electric field E in theelectromagnetic wave relative to the axis of stretching. Polarizingeffectiveness of such films is determined by the concentration of iodineor other organic coloring agent and the degree of ordering of thepolymer molecules. Such films feature the so-called positive dielectricanisotropy and positive dichroism. This means that the dipole moments ofoptical transition of molecules, which are responsible for absorption oflight, are oriented along the direction of stretching. At the same timethe ellipsoids of the angle dependence of the real and imaginary partsof the refraction coefficient have an extended form. Polarizers obtainedfrom the described above films are termed O-type, since the “ordinary”wave will pass through, while the “extraordinary” will not.

Despite the high polarizing effectiveness, these polarizers havesubstantial drawbacks. These are low light and thermal resistance, largerequired thickness to achieve high effectiveness. One of the maindrawbacks featured by the two cross-oriented polarizers is the hightransmission of light incident at an angle (±0.45) to the surface of thepolarizers.

There are LC displays that utilize polarizers on the inside surfaces ofthe glass plates (RU 2120651, 1998). The polarizers used in suchdisplays are thin films with ordered molecular structure of the liquidcrystal polarizer (LCP) (U.S. Pat. No. 5,739,296, 1998). The flatmolecules of such LCP are grouped together into the so-calleddirectionally ordered bunches—supramolecular complexes. The planes ofthe individual molecules, and thus their inherent dipole moments ofoptical transition, are oriented perpendicular to the axis ofmacroscopical orientation of the produced film. To create such structureone uses the liquid-crystalline state of the LCP, where the moleculesare already ordered locally, while in one- or two-dimensional blocksoriented relative to each other. When applied onto a surface with anadditional external alignment force, such substance assumes themacroscopical orientation, which upon dehydrating not only reins butcould also improve on its own. The resulting axis of polarization isalong the direction of the external aligning action. In this case theellipsoids of the angle dependence of the real and imaginary parts ofthe refraction coefficient have disk-like shape,

The latter polarizers are termed E-type, since “extraordinary” wave isnow transmitted and “ordinary” is blocked.

Such polarizer features a number of substantial disadvantages, whichlimit its applicability. One of those is the insufficient polarizingeffectiveness, and some transmission of light has been registered troughtwo parallel cross-oriented polarizers of this type with the incidentunpolarized light at an angle to their surfaces. This effect isespecially prominent when at least one of the polarizers has thediffused-reflection coating, which is used in the majority of LCdisplays.

SUMMARY

The technical results herein are: the improvement of the anglecharacteristics of polarizers and LC displays, the reduction of theamount of transmitted unpolarized light by a single as well asparallel-coupled polarizers while retaining their thickness, theenhancement of their polarizing effectiveness, improved contract,widening of the viewing angle as well as elimination of the ‘gray field’effect during operation.

These technical results are achieved by utilizing combinations of E- andO-type polarizers. Here, the O-type polarizer provides the hightransmission of light during open state, while E-type polarizer providesthe high angle characteristics in the closed state. The E-type polarizerwith the optimal characteristics, which correspond to the high value ofthe coefficient of absorption along the normal to the plane of thepolarizer is obtained by forming a thin film of molecular-oriented LCP(liquid crystal polarizer) on the surface of O-type polarizer. Theorientation of the molecules is such that their dipole moments of theoptical molecular transit are distributed in the plane perpendicular tothe axis of polarization and the surface of O-type polarizer.

The display could be manufactured according to known techniques andcould be produced with a known design not to exclude the option toutilize some original, and possibly not yet described methods andarrangement. An aspect of interest in this disclosure from otherdisclosed prototypes is in the use of a combination of different typesof polarizers. The disclosed here polarizer utilizing a composition ofat least two layers, one of each is O-polarizer and another isE-polarizer, could be used in any field of technology which quires suchcharacteristics, in particular in the field of liquid crystal displaysof different applications.

DRAWINGS

The present disclosure is illustrated in part by the enclosed drawingsof which:

FIG. 1 is a diagrammatic depiction of the first embodiment;

FIG. 2 is a diagrammatic depiction of the second embodiment;

FIG. 3 is a diagrammatic depiction of the third embodiment.

DETAILED DESCRIPTION

Envisioned in this disclosure is the following.

In a first embodiment, as seen in FIG. 1, there is a liquid crystaldisplay containing at least one layer of the liquid crystal placedbetween two plates. On each plate there is disposed or applied at leastone electrode, a system of electrodes, or an active matrix; and at leastone layer of polarizer. At least one layer of polarizer is an O-typepolarizer and at least one layer of polarizer is an E-type polarizer.

In a display of the first embodiment, the O-type polarizer is preferablyan iodine-polyvinyl, iodine-polyvinylene or polyvinylene polarizer. TheE-type polarizer is preferably formed as a thin film comprised of aplurality of supramolecular complexes of one or several organicmaterials, the supramolecular complexes being generally unidirectionallyoriented in order to ensure polarization of incident light.

A dichroic polarizer is preferably used as the E-type polarizer, thedichroic polarizer comprising a film of oriented molecules of an organiccompound. In this film, the organic compound is such that the main axesof the ellipsoids of the real and imaginary part of the anisotropicrefraction coefficient of the compound forming the film is in the rangeof at least one band of absorption wavelength. The following is true foran area with linear dimensions no less than the wavelength:K₁ ≥ K₂ > K₃  and $\frac{\left( {n_{1} + n_{2}} \right)}{2} > n_{3}$where, K₁, K₂, K₃ and n₁, n₂, n₃, are the major or main values of thereal and imaginary part, respectively, of the axes of the ellipsoid. Inaddition or alternatively, the film is characterized by the fact thatfor two films with crossed polarization axes, the transmission of lightdoes not increase in at least a certain range of wavelengths, when itsdirection departs, deviates, or deflects from the normal to thepolarizer plane. The directions corresponding to the maximum and minimumvalues of the imaginary part of the refraction coefficient lie in theplane parallel to the plane of the substrate.

The organic compound of which the E-type polarizer is formed, comprisesat least one organic substance which includes at least one ionogenicgroup, which provides solubility in polar and non-polar solvents inorder to create the lyotropic liquid-crystal phase and at least onecounter-ion, which in the process of formation of the film eitherremains in the structure of the molecules or does not.

The organic substance comprises at least one organic dye capable ofabsorption in at least one of the following ranges: from 200 through 400nm, 400 through 700 nm, or 0.7 through 13 μm. Further, at least one ofthe polarizers is an internal polarizer and applied on the internal sideof one of the glass plates. The layers of the polarizers of O- andE-types are applied to the inside and/or the outside of one plate orinside and/or the outside of both of the plates. Also, the optical axesof polarizers E- and O-types are mutually parallel or mutuallyperpendicular.

The plates described herein are preferably fabricated out of glass,plastic, semiconductor material, metal or any other material suitablefor their manufacture. The plates may all be made of the same materialsor different materials. However, at least one of the plates ispreferably optically transparent in the working area of light spectrum.The display also has the means of obtaining colored images.

The liquid crystals are comprised of a nematic, smectic, or cholestericliquid crystals or liquid crystals of any other chemical classes ortheir mixtures.

The display also contains at least one alignment layer and/or at leastone diffuse-reflecting layer and/or at least one phase-shifting layerand/or at least one birefringent layer and/or at least one conductinglayer and/or at least one protective layer and/or at least one isotropiclayer and/or at least one anisotropic layer and/or at least oneinsulating layer and/or at least one alignment layer and/or at least onediffuse- or mirror-reflecting layer and/or a layer simultaneouslyfunctioning as at least two of the above layers.

In this disclosure, the E-type polarizer may also function as aphase-shifting layer, and/or birefringent layer, and/or alignment layer,and/or protective layer, and/or a layer functioning as at least two ofthe foregoing layers.

The device also includes spacers on at least one of the plates to limitthe distance of separation between the plates.

The display is of either the transmissive or reflective type.

In a second embodiment as seen in FIG. 2, the display contains at leastone layer of liquid crystal placed between two plates. On each plate,there has been disposed or formed at least one electrode or a system ofelectrodes, or an active matrix, wherein on one of the plates there hasbeen disposed a diffuse- or mirror-reflecting layer, and on one of theplates there has been disposed at least one layer of an O-type polarizerand at least one layer of an E-type polarizer.

In this second embodiment the layers of polarizers of O- and E-type areapplied to different sides of a plate. In this instance, the O-typepolarizer is formed using iodine-polyvinyl, iodine-polyvinylene orpolyvinylene polarizer, and the E-type polarizer comprises a thin filmcomprised of a plurality of supramolecular complexes of one or severalorganic compounds, wherein the supramolecular complexes areunidirectionally oriented in order to polarize the incident light.

A dichroic polarizer is preferably used as the E-type polarizer, thedichroic polarizer comprising a film of oriented molecules of an organiccompound. In this film, the organic compound is such that the main axesof the ellipsoids of the real and imaginary part of the anisotropicrefraction coefficient of the compound forming the film is in the rangeof at least one band of absorption wavelength. The following is true foran area with the linear dimensions no less than the wavelength:K₁ ≥ K₂ > K₃  and $\frac{\left( {n_{1} + n_{2}} \right)}{2} > n_{3}$where, K₁, K₂, K₃ and n₁, n₂, n₃, are the major or main values of thereal and imaginary part. Accordingly, the axes of the ellipsoid, and/orthe film is characterized by the fact that for two films with crossedpolarization axes the transmission of light does not increase in atleast a certain range of wavelengths when its direction departs,deviates, or deflects from the normal to the polarizer plane.

In this embodiment, the directions which correspond to the maximum andminimum values of the imaginary part of the refraction coefficient liein the plane parallel to the plane of the substrate. Also, the E-typepolarizer comprises at least one organic compound, which comprises atleast one ionogenic group, which provides its solubility in polar andnon-polar solvents in order to create the lyotropic liquid crystalphase, and at least one counter-ion, which in the process of formationof the film either remains in the structure of the molecule or does not.

This embodiment includes at least one organic dye, capable of absorptionin at least one of the following ranges: from 200 through 400 nm, or 400through 700 nm, or from 0.7 through 13 μm, used as the organic compoundof the polarizer. Further, the plates are fabricated out of glass,plastic, semiconductor, metal or any other material suitable for theirmanufacture, and in addition, the same or different materials could beused for either of the plates. Also it is preferred that at least one ofthe plates is optically transparent in the working range of lightspectrum.

The display of this embodiment also includes means for obtaining coloredimage. Further, the embodiment includes liquid crystals comprised of anematic, smectic or cholesteric liquid crystals, or liquid crystals ofany other chemical classes or their mixtures. This second embodimentalso includes at least one alignment layer and/or at least onediffuse-reflecting layer, and/or at least one phase-shifting layer,and/or at least one birefringent layer, and/or at least one conductinglayer, and/or at least one protective layer, and/or at least oneisotropic layer and/or anisotropic layer, and/or at least one insulatinglayer and/or at least one alignment layer, and/or a layer simultaneouslyfunctioning as at least two of the above layers.

The layer of the E-type polarizer in this second embodiment functionssimultaneously as a phase-shifting layer, and/or birefringent layer,and/or alignment layer, and/or protective layer, and/or a layerfunctioning as at least two of the above layers. Also, at least on oneof the plates there are the spacers to limit the distance of separationbetween the plates.

In a third embodiment as seen in FIG. 3, there is a polarizer,comprising at least two layers, at least one of which is an O-typepolarizer and at least one of the polarizer layers is an E-typepolarizer. In this embodiment, the O-type polarizer is preferably aniodine-polyvinyl, iodine-polyvinylene or polyvinylene polarizer, and theE-type polarizer used is a thin film comprised of a plurality ofsupramolecular complexes of one or several organic compounds, whereinthe supramolecular complexes are unidirectionally oriented in adetermined direction in order to polarize the incident light.

The E-type polarizer is a dichroic polarizer. This dichroic polarizercomprises a film of oriented molecules of an organic compound, whereinthe main axes of the ellipsoids of the real and imaginary part of ananisotropic refraction coefficient of the compound forming the film isin the range of at least one band of absorption wavelengths. Thefollowing is true for an area with the linear dimensions no less thanthe wavelength: K₁ ≥ K₂ > K₃  and$\frac{\left( {n_{1} + n_{2}} \right)}{2} > n_{3}$where, K₁, K₂, K₃ and n₁, n₂, n₃, are the major or main values of thereal and imaginary part, respectively, of the axes of the ellipsoid,and/or for two films with crossed polarization axes the transmission oflight does not increase in at least a certain range of wavelengths whenits direction departs, deviates, deflects from the normal to thepolarizer plane.

The E-type polarizer comprises at least one organic compound, whichincludes at least one ionogenic group, which provides its solubility inpolar and non-polar solvents in order to create the lyotropic liquidcrystal phase and at least one counter-ion, which in the process offormation of the film either remains in the structure of the molecule ornot.

This embodiment includes as the organic compound at least one organicdye, capable of absorption in at least one of the following ranges: from200 through 400 nm, or 400 through 700 nm, or from 0.7 through 13 μm.The layer of E-type polarizer is applied on top of the layer of O-typepolarizer and/or vice versa. The polarizer is preferably multi-layeredwith any possible combination of E- and O-type polarizer layers.Preferably, the thickness of each layer is designed to providepolarizing effectiveness of 70 to 100%.

Further, the polarizer may include an additional mirror- ordiffuse-reflecting layer applied onto its surface from the side of theE- or O-type polarizer layer or both.

Making use of the methods of assembly of LC displays, one can list anumber of various configurations.

Design 1. One of the possible LC display designs could be a transmissivedisplay with internal polarizers. One of the polarizers in such adisplay design could be the single-layered E-type polarizer manufacturedaccording to the method described in (U.S. Pat. No. 5,739,296, 1998),applied to one of the glass plates (first plate). This polarizer has acrystalline structure of oriented supramolecular complexes of an organicmatter, most commonly dyes. Various materials and polarizers of thistype are widely known and used (U.S. Pat. No. 5,739,296, 1998). Suchpolarizer has negative dielectrical anisotropy and negative dichroism;it has inherently high polarizing and operational characteristics. Theother polarizer could be formed by application onto another glass plateof display, and it is multi-layered, in particular double-layered. Thefirst of the layers could be, for example, a layer of O-type polarizer,which features positive dielectrical anisotropy and positive dichroism.This layer could be built with the oriented molecules of polyvinylalcohol colored by iodine. It is possible, for example, to first obtainthis polarizer as a thin film and then apply it to the inside of theglass plate, which already has the electrode pattern and the alignmentlayer applied on it. However; the method of application and arrangementof the components other than the polarizer could vary. On top of theabove-mentioned O-type polarizer one could apply a layer of E-typepolarizer, either directly on a O-type polarizer layer or on anintermediate layer, which could be isotopic as well as anisotropic. Inthis example design the E-type polarizer could be utilized also as thealignment layer and/or as the birefringent layer, and/or as thephase-shifting layers. This option in addition to the result achieved bythe different designs of the layers in polarizer and a display alsoallows decreasing the thickness of the display.

The stacking order of O-type and E-type layers, however, could be otherthan described above, which will not change the resultantcharacteristics. In particular, the E-type polarizer could be appliedonto the display plate where the electrode pattern or an active matrixalong with the alignment layer have already been applied, and the O-Typepolarizer could be applied on top of that, also by the direct forming ofa layer on the surface or by the gluing of a mediator film formed inadvance.

The described above double-layered polarizers correspond to thepolarizers according to the claims. The mentioned configuration oflayers could be changed according to the requirements—it could be higheror could be different The layers of O- and E-type polarizers canalternate as well as double.

In the described display design the first display plate could be made ofa single-layered O-type polarizer made out of oriented molecules ofpolyvinyl-alcohol colored by iodine.

In a different arrangement of a transmissive LCD with internalpolarizers, each polarizer plate is made out of the multi-layeredpolarizers with the same or distinct layering sequence and combinationof E- and O-type polarizers.

Design 2. Another configuration of a transmissive LC which can bedesigned in accordance with the claims of the invention, could beobtained by applying different sequences of polarizers in variablecombinations on the outside of the plates. Usually protective coatingsfulfill this function for this sort of structures. However, since theinvention does not limit the configuration of LC display to any onekind, but characterize the polarizers' structure only, we will not focuson the description of all structures details of the known LCD designs.These include the arrangement of spacers, the method of joining of thedisplay plates, the manufacturing and application of the electrodes andother elements as well as the choice of materials for them, which couldbe a subject of another invention.

Design 3. A particular attention should be paid to the design of atransmissive LC display with a “mixed” sequencing of polarizing layers.The sequencing could be any of the above-mentioned kinds utilizingdifferent types of polarizers, which could be applied on either side ofthe plates. The choice could vary for different designs and the sequenceis determined by the particular requirements of the intendedapplication. This flexibility of possible combinations and sequencing ofpolarizer layers allows substantial broadening of functionalpossibilities of displays.

Design 4. The most promising, according to the obtained results, is thereflective LC display, where one of its sides is non-transparent i.e. areflecting layer (film or plate) which is mirror-reflecting ordiffusive-reflecting in the working display range is placed either atthe internal or external rear plate.

The configuration of polarizing layers in the reflective display couldbe the same as in the case of the transmitting display described above.The difference is in the option to place the polarizer layers on therear plate side. In case the reflective layer is placed behind the rearplate then the combination of polarizers could be any. In case thereflective layer is placed at the internal side of the rear displayplate, or the plate is not transparent itself and it is reflectiveitself, in this case rear plate polarizers could be internal only.

All the designs of LC displays and the combined polarizer, despite theirvariety, do not deplete the list of possible arrangements determined bythe claims of the disclosed invention. However, according to theexperimental results, the use of the described designs with differentpolarizer sequences and combinations allows substantially enhancetechnical characteristics of LC displays. Here, all the displaysmanufactured featured improved angle characteristics of polarizers aswell as the display as a whole. The displays exhibited negligible amountof transmitted unpolarized light by a single polarizer as well as by twoparallel polarizers. In addition to that, improvements likesubstantially enhanced polarizing effectiveness and contrast ratio;viewing angle was broadened up to 180° and an absence of the “grayeffect” has been registered. All of the mentioned improvements can beobtained with various assembly designs. This greatly broadens functionalpossibilities of high quality LC displays and allows unification of themanufacturing process of different displays hence lowering the cost.

1. A liquid crystal display comprising a first plate and a second plate;and at least one layer of liquid crystal placed between the first andsecond plates, wherein on each of the plates there is formed at leastone electrode or a system of electrodes or an active matrix, wherein thefirst plate comprises a reflecting layer, and the second plate comprisesat least one layer of O-type polarizer having negative dielectricalanisotropy and negative dichroism and at least one E-type polarizerhaving positive dielectrical anisotropy and positive dichroism.
 2. Theliquid crystal display according to claim 1 wherein the O-type polarizerand the E-type polarizer are applied to different sides of the secondplate.
 3. The liquid crystal display according to any of claims 1-2wherein the O-type polarizer is formed using iodine-polyvinyl,iodine-polyvinylene or polyvinylene polarizer, and the E-type polarizerused is a thin film comprised of a plurality of supramolecular complexesof one or several organic matters, wherein supramolecular complexes areuniformly oriented in order to polarize the incident light.
 4. Theliquid crystal display to claim 1 wherein the function of the E-typepolarizer is played by the dichroic polarizer, which is realized as afilm of oriented molecules of an organic matter, and characterized bythe fact that for the main aces of the ellipsoids of the real andimaginary part of its anisotropic coefficient of refraction in the rangeof at least one band of absorption wavelengths, the following is truefor an area with the linear dimensions no less than the wavelength:K₁ ≥ K₂ > K₃  and $\frac{\left( {n_{1} + n_{2}} \right)}{2} > n_{3}$where, K₁, K₂, K₃ and n₁, n₂, n₃, are main values of the real andimaginary part respectively, of the axes of the ellipsoid, and/or thefilm is characterized by the fact that for two films with crossedpolarization axes the transmission of light does not increase for atleast a certain range of wavelengths with its direction declined fromthe normal to the polarizer plane.
 5. The liquid crystal displayaccording to claim 4 wherein the directions which correspond to themaximum and minimum values of the imaginary part of the refractioncoefficient lay in the plane parallel to the plane of the plate.
 6. Theliquid crystal display according to claim 1 wherein the E-type polarizeruses at least one organic matter, chemical formula of which features atleast one ionogenic group, which provides its solubility in polar andnon-polar solvents in order to create the lyotropic liquid crystalphase, and at least one counter-ion, which in the process of formationof the film either remains in the structure of the molecule or not. 7.The liquid crystal display according to claim 6 wherein at least oneorganic dye, capable of absorption in at least one of the followingranges: from 200 through 400 nm, or 400 through 700 nm, or 0.7 through13 μm, is used as the organic matter of the polarizer.
 8. The liquidcrystal display according to claim 1 wherein the plates are made out ofeither glass, plastic, semiconductor, metal or any other material usedfor their manufacturing, and the same or different materials are usedfor either of the plates.
 9. The liquid crystal display according toclaim 1 wherein at least one of the plates is optically transparent inthe working range of light spectrum.
 10. The liquid crystal displayaccording to claim 1 further comprising a means of obtaining coloredimage.
 11. The liquid crystal display according to claim 1 wherein anematic or smectic or cholesteric or their mixtures is used as thesubstance of liquid crystal.
 12. The liquid crystal display according toclaim 1 further comprising at least one alignment layer and or at leastone diffuse-reflecting layer and/or at least one phase-shifting layerand/or at least one birefringent layer and/or at least one conductinglayer and/or at least one protective layer and/or at least one isotropiclayer and/or anisotropic layer and/or at least one dielectric layerand/or at least one alignment layer and/or at least one diffuse- orreflecting layer and/or a layer functioning as at least two of the abovelayers.
 13. The liquid crystal display according to claim 1 wherein theE-type polarizer is at the same time functioning as a phase-shiftinglayer, and/or a birefringent layer, and/or an alignment layer, and/or aprotective layer, and/or a layer functioning as at least two of theabove layers.
 14. The liquid crystal display according to claim 1wherein at least on one of the plates there are spacers controlling thedistance of separation between the plates.
 15. The liquid crystaldisplay according to claim 1 wherein the reflecting layer isdiffuse-reflecting.
 16. The liquid crystal display according to claim 1wherein the reflecting layer is mirror-reflecting.
 17. The liquidcrystal display according to claim 2 wherein the O-type polarizer isapplied to the inside of the second plate and the E-type polarizer isapplied to the outside of the second plate.